Stress-induced poor sleep: Sex differences, vulnerability & resilience factors Caring for a child with a neurodevelopmental disorder is a source of chronic stress that can impair sleep, but not for all parents. There is little understanding of the exact psychological or biological mechanisms linking stress and sleep behavior, or the vulnerability and resiliency factors that promote or dampen the stress-sleep relationship. One plausible vulnerability factor is being high in stress sensitivity-certain psychological and biological processes that promote vigilance and arousal. The goal of the proposed project is to unpack the sleep-stress cycle, by examining: 1) stress-sensitivity related psychobiological predictors (emotional and cognitive reactivity and regulation and daily cortisol) of daily sleep (delayed onset, short duration, low efficiency, poor subjective quality); and 2) the ensuing effects of sleep on stress sensitivity variables. Individuals do not exist in a vacuum, and, if partnered, supportive or conflict-laden interactions within a partner dyad can dampen or exacerbate psychological and biological stress responses, further impacting sleep patterns. Therefore, our third goal is to examine if spousal/partner interactions compound or mitigate the effects of stress sensitivity on sleep. To this end, we propose to examine stress and sleep in a sample stratified on chronic stress, with 50 high stress couples (parents of children with Autism Spectrum Disorder or ASD) and 50 low stress couples, demographically similar parents of typically developing children (100 pairs total). We will efficiently piggyback the design and measures onto an already-funded R01 study on stress- induced cell aging that is currently following the sample of mothers. In the proposed project we will recruit their partners and add measures of objective sleep actigraphy, subjective sleep quality, daily psychological stress processes, and diurnal measures of cortisol over 10 consecutive days. The aims of the study are: 1) To assess whether daily stress sensitivity predicts poorer night to night sleep parameters within subjects and across the sample and explains the poorer sleep of the parents of children with ASD compared to control parents; 2) To assess whether supportive vs. strained partner interactions moderate the stress sensitivity-sleep relationship; and 3) To determine whether sex differences exist in the stress-sleep relationships in the above aims. Secondarily, using the R01-funded measures of stress-related biological aging, we will be able to test whether poor sleep, averaged across the 10 days of measurement, is associated with marked changes in biomarkers of chronic stress -- lower vagal tone, dysregulation of the HPA axis negative feedback loop, and shorter leukocyte telomere length. The proposed study answers unique and novel questions about the stress- sleep cycle with remarkable cost savings and efficiency by piggybacking onto the large longitudinal R01 study. Identifying the stress-related influences on nightly sleep within the parent dyads, and the resulting impact of sleep on stress markers, will have implications for both basic research and interventions.